Quality assurance in screening mammograms: first results of the Brussels project for breast cancer screening

EuropeanSociety of Mastology Abstracts 327 Analysis of ductal carcinoma in situ detected at screening has shown bias towards high grade disease; the consensus of opinion amongst pathologists is the detection of high grade DCIS is important in preventing the subsequent development of invasive cancer some years later. Similarly our analysis his shown that identification of high grade DCIS as microcalcitications facilitates the detection of small high grade invasive tumours at a stage when treatment is much more likely to be effective. There is increasing interest in the role of screening in the surveillance of patients at increased risk of breast cancer - those with a significant family history and those with previous biopsy showing epithelial changes associated with increased risk. As yet there is no consensus on how the two manage these patients. Women shown to be genetically predisposed as carriers of the BRCAl or BRCA2 gene should be counselled for possible bilateral mastectomies while those with lesser risk may benefit from regular mammographic screening. However, the evidence for any mortality benefit from such screening remains sparse. Achieving pre-operative diagnosis is important for patient well being and the reintroduction of core biopsy using rapid fire guns has allowed many centres to improve their pre-operative diagnosis rates to above 95% and at the same time dramatically reduce the number of diagnosis surgical biopsies performed for what proves to be benign disease. More recently in the UK some analysis of overall breast cancer mortality benefit has suggested that breast cancer screening may be showing early signs in effect with mortality rates falling, particularly in women in the 50 to 70 age range. Analysis has shown that this fall in mortality is associated with improvement in breast cancer stage rather than being attributable to improved treatment. Similarly data in Nottingham over a 20 year period has demonstrated a dramatic fall in breast cancer mortality which correlates closely with a significant fall in tumour size at the time of diagnosis. This data is very encouraging for a predicted significant fall in mortality attributable to earlier diagnosis by screening.

A way to reduce the number of benign breast biopsies in a screening programme G Querci della Rovere, M Morgan, A Patel, Y Steele, R Warren Breast Screening Service, St Margaret’s Hospital, Epping, UK; The Royal Marsden Hospital, Sutton, UK In breast screening it is imperative to minimize the number of benign biopsies. During the period from November lst, 1987 to January lst, 1994 at the Breast Screening Service in Epping, we detected 402 carcinomas (72,391 screened women, prevalence 42,745503 ca, incidence 29,64699 ca), observed 97 interval carcinomas and carried out 100 benign biopsies. The benign malignant ratio was 1:4. The radiological features of the benign biopsies were as follows: Microcalcifications 45%, circumscribed lesion 20%, asymmetry or distortion 19%, stellate lesion 16%. We reviewed the combined (cytological-radiological) levels of suspicion and found that 58% of the benign biopsies were C2R3 or C3R3. Of the 402 carcinomas only two cases had combined cytologicalradiological levels of suspicion in the C2R3 or C3R3 groups. We conclude that, at least in our experience, we could reduce by 58% the number of benign biopsies by adopting a policy of careful follow-up for C2R3 and C3R3 lesions.

The aim of this study was to assess the effect of hormone replacement therapy (HRT) on the sensitivity of mammographic screening by comparing HRT usage by women with screen detected cancers and HRT usage by women presenting with interval cancers. Information about HRT usage has been collected on all women attending for screening since 1991. In women with interval cancers their HRT usage at their previous ‘normal’ screen was examined. There have been 1031 cancers detected by screening in the West of Scotland between May 1988 and November 1996. Of these women, 175 (17%) were taking HRT at the time of their screening episode. Over the same time period 359 women have presented with interval cancers. Of these women 84 (23%) were taking HRT at their previous ‘normal’ screen. A significantly higher number of women with interval cancers were taking HRT (&i-squared 7.2 p < 0.01). Comparing HRT usage in women presenting with interval cancers in the first year after a ‘normal’ screen a significantly higher number were using HRT, 26 out of 76 women (34%) compared with screen detected cancers (chi squared 14.1 p < 0.005). Our results support the idea that women taking HRT are significantly more likely to have a cancer missed at screening and that HRT usage is therefore likely to reduce the sensitivity of mammographic screening. This is of importance as women in the screening population (aged 50-65) are those most likely to use HRT and HRT usage in general is increasing.

Quality assurancein screening mammograms: first results of the Brussels project for breast cancer screening A GrivegnCe,C Bourdon, F Renard J. Bordet Institute; Brussels and Public Health School of UCL; Brussels, Belgium Context and objectives: the Brussels Project for Breast Cancer Screening aims to implement a quality assurance system for screening mammograms, through the organization of double reading and follow up of quality indicators. Material and methods: at 13 March 1996, 15 months after the project started, 10 radiology centres actively participated; in this first period, the quality indicators were studied only for centres who practiced uniquely screening mammography. 8946 double readings have been performed within this period. Follow up results for women with a positive screening were searched by contacting the radiologist or the practitioner. Results: recall rates were 7.8%, biopsy rate was OS%, crude cancer detection rate was 3 for thousand, positive predictive value of biopsy indication was 57%, malignant to benign biopsy ratio is 1.3. Conclusion: in the centers studied, the recall rate is too high, but this does not result in an excess of biopsies: the cancer detection rate corresponds to the expected rate in a screening programme. In the future, notification of the type of mammogram should allow calculate of quality indicators for all participating centres.

Results of diagnostic examinations and pathological grade in screen-detectedductal carcinoma in situ of the breast (DCIS)

J Litherland, S Stallard

A Sapino, S Bianchi, R Arisio, E Berardengo,A Ponti, G Ru, D Giorgi, D Morrone, V Marra, V Vezzosi, M Bongioanni, A Frigerio, M Rosselli de1Turco, MP Mano, C Coluccia, R Giani, V Distante, R Simoncini, G Cardona,N Segnan

West of Scotland Breast Screening Centre and the Western Infirmary, Glasgow, UK

1st Anatomia Patologica, Univ. Torino; 1st. Anatomia Patologica, Univ. Firenze; Serv. Anatomia Patologica,

The effect of hormone replacement therapy on the sensitivity of mammographic screening